Chest
Critical CareJournal ArticleThe Diagnosis and Management of Neuromuscular Diseases Causing Respiratory Failure
Section snippets
The Neuroanatomy of Respiration
The brain stem is the primary center for the central control of respiration. This control occurs at a subconscious level and results in the rhythmic contraction and relaxation of the respiratory muscles. This automatic state can be temporarily overridden by voluntary mechanisms or by reflex actions such as coughing or sneezing.2 These voluntary mechanisms are essential for speech and phonation. The cortical centers for the voluntary control of respiration are presently not well localized.
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An Anatomic Approach to the Diagnosis of Neuromuscular Diseases
Figure 1 demonstrates the neuroanatomy of the respiratory muscles. Only lesions along the pathways demonstrated in this figure can produce weakness of the respiratory muscles. Diagnosis of the cause of neuromuscular dysfunction is best made by anatomically localizing the site of the lesion by history and physical examination. Once the anatomic site (ie, myoneural junction, spinal cord) is determined, the correct diagnosis can be confirmed by associated nonneurologic symptoms and other tests.
Central Disorders
Stroke is a common cause of upper motor neuron respiratory dysfunction. Strokes occur most frequently in the middle cerebral artery distribution11 and affect the voluntary system of respiration. Strokes can alter respiratory function in several ways. First, they often affect the muscles that protect the upper airway and maintain its patency. Horner et al12 found that among 47 patients with stroke, one half showed signs of aspiration. Although patients with brain-stem strokes with resultant
Precipitating Factors
Precipitating factors are often the immediate cause for ICU admission of patients with neuromuscular disease. The identification of such factors is essential because they may be more amenable to therapy than the neuromuscular disease itself. Upper airway obstruction and aspiration should be suspected in patients with bulbar dysfunction, whereas microatelectasis and lower respiratory tract infections are common among all patients with generalized weakness. Pulmonary hypertension and right-sided
ACKNOWLEDGMENT
The authors thank Dr. June Melloni-Kelly for her superb illustration. Thanks are also extended to Dr. Neal H. Cohen and Dr. Anthony Campagna for their critical review of the manuscript.
References (48)
Applied respiratory physiology
(1987)- et al.
Respiratory effects of pneumotaxic center lesions and subsequent vagotomy in chronic cats
Respir Physiol
(1975) - et al.
Atelectasis and neuromuscular respiratory failure
Chest
(1984) - et al.
Respiratory complications and management of spinal cord injuries
Chest
(1990) - et al.
Adverse effects of drugs on the respiratory muscles
Clin Chest Med
(1990) - et al.
Clinical manifestations of inspiratory muscle fatigue
Am J Med
(1982) Autonomic dysfunction in the Guillain-Barre syndrome
Am J Med
(1971)- et al.
The respiratory muscles
N Engl J Med
(1982) - et al.
Neural regulation of respiration
Cranial nerve nuclei, the reticular formation and biogenic amine-containing neurons